Add neighbor config option to bypass as-path loop detection on local (static) routes

Author: floatingstatic

api/attribute.pb.go

@@ -621,6 +621,7 @@ message PeerConf {
   bool replace_peer_asn = 14;
   bool admin_down = 15;
   bool send_software_version = 16;
+  bool allow_aspath_loop_local = 17;
 }
 
 message PeerGroupConf {

api/capability.pb.go

@@ -109,6 +109,7 @@ func setDefaultNeighborConfigValuesWithViper(v *viper.Viper, n *Neighbor, g *Glo
 
 	n.State.PeerAs = n.Config.PeerAs
 	n.AsPathOptions.State.AllowOwnAs = n.AsPathOptions.Config.AllowOwnAs
+	n.AsPathOptions.State.AllowAsPathLoopLocal = n.AsPathOptions.Config.AllowAsPathLoopLocal
 
 	if !v.IsSet("neighbor.error-handling.config.treat-as-withdraw") {
 		n.ErrorHandling.Config.TreatAsWithdraw = true

api/gobgp.pb.go

@@ -466,21 +466,22 @@ func NewPeerFromConfigStruct(pconf *Neighbor) *api.Peer {
 	return &api.Peer{
 		ApplyPolicy: newApplyPolicyFromConfigStruct(&pconf.ApplyPolicy),
 		Conf: &api.PeerConf{
-			NeighborAddress:     pconf.Config.NeighborAddress,
-			PeerAsn:             pconf.Config.PeerAs,
-			LocalAsn:            pconf.Config.LocalAs,
-			Type:                api.PeerType(pconf.Config.PeerType.ToInt()),
-			AuthPassword:        pconf.Config.AuthPassword,
-			RouteFlapDamping:    pconf.Config.RouteFlapDamping,
-			Description:         pconf.Config.Description,
-			PeerGroup:           pconf.Config.PeerGroup,
-			NeighborInterface:   pconf.Config.NeighborInterface,
-			Vrf:                 pconf.Config.Vrf,
-			AllowOwnAsn:         uint32(pconf.AsPathOptions.Config.AllowOwnAs),
-			RemovePrivate:       removePrivate,
-			ReplacePeerAsn:      pconf.AsPathOptions.Config.ReplacePeerAs,
-			AdminDown:           pconf.Config.AdminDown,
-			SendSoftwareVersion: pconf.Config.SendSoftwareVersion,
+			NeighborAddress:      pconf.Config.NeighborAddress,
+			PeerAsn:              pconf.Config.PeerAs,
+			LocalAsn:             pconf.Config.LocalAs,
+			Type:                 api.PeerType(pconf.Config.PeerType.ToInt()),
+			AuthPassword:         pconf.Config.AuthPassword,
+			RouteFlapDamping:     pconf.Config.RouteFlapDamping,
+			Description:          pconf.Config.Description,
+			PeerGroup:            pconf.Config.PeerGroup,
+			NeighborInterface:    pconf.Config.NeighborInterface,
+			Vrf:                  pconf.Config.Vrf,
+			AllowOwnAsn:          uint32(pconf.AsPathOptions.Config.AllowOwnAs),
+			AllowAspathLoopLocal: pconf.AsPathOptions.Config.AllowAsPathLoopLocal,
+			RemovePrivate:        removePrivate,
+			ReplacePeerAsn:       pconf.AsPathOptions.Config.ReplacePeerAs,
+			AdminDown:            pconf.Config.AdminDown,
+			SendSoftwareVersion:  pconf.Config.SendSoftwareVersion,
 		},
 		State: &api.PeerState{
 			SessionState: api.PeerState_SessionState(api.PeerState_SessionState_value[strings.ToUpper(string(s.SessionState))]),

api/gobgp.proto

@@ -691,6 +691,7 @@ func newNeighborFromAPIStruct(a *api.Peer) (*oc.Neighbor, error) {
 		pconf.Config.Vrf = a.Conf.Vrf
 		pconf.AsPathOptions.Config.AllowOwnAs = uint8(a.Conf.AllowOwnAsn)
 		pconf.AsPathOptions.Config.ReplacePeerAs = a.Conf.ReplacePeerAsn
+		pconf.AsPathOptions.Config.AllowAsPathLoopLocal = a.Conf.AllowAspathLoopLocal
 		pconf.Config.SendSoftwareVersion = a.Conf.SendSoftwareVersion
 
 		switch a.Conf.RemovePrivate {

pkg/config/oc/bgp_configs.go

@@ -158,6 +158,12 @@ func (peer *peer) TableID() string {
 	return peer.tableId
 }
 
+func (peer *peer) allowAsPathLoopLocal() bool {
+	peer.fsm.lock.RLock()
+	defer peer.fsm.lock.RUnlock()
+	return peer.fsm.pConf.AsPathOptions.Config.AllowAsPathLoopLocal
+}
+
 func (peer *peer) isIBGPPeer() bool {
 	peer.fsm.lock.RLock()
 	defer peer.fsm.lock.RUnlock()

pkg/config/oc/default.go

@@ -691,8 +691,15 @@ func filterpath(peer *peer, path, old *table.Path) *table.Path {
 		return nil
 	}
 
-	if !peer.isRouteServerClient() && isASLoop(peer, path) && !path.IsLocal() {
-		return nil
+	if !peer.isRouteServerClient() && isASLoop(peer, path) {
+		// Do not filter local (static) routes with as-path loop
+		// if configured to bypass these checks in the peer
+		// as-path options config.
+		if path.IsLocal() && !peer.allowAsPathLoopLocal() {
+			return nil
+		} else if !path.IsLocal() {
+			return nil
+		}
 	}
 	return path
 }